A person buys a watch for ₹900 and sells it for ₹1080. Find the profit percentage.

लाभ = विक्रय मूल्य - क्रय मूल्य = 1080 - 900 = ₹180। लाभ % = (लाभ / क्रय मूल्य) * 100 = (180 / 900) * 100 = 20%।